The farthest galaxy in the universe

Chemical signatures give the distance to the farthest constellation, which experts say explains the true end of the visible universe.

Image credit: Vincentiu Solomon Unsplash

A team of astronauts used the Keck I telescope to measure the distance to an ancient galaxy. They took out the target galaxy GN-z11 not only the oldest galaxy but also the farthest ones and explained the true end of the universe itself. The team hopes that this study can shed light on a time of cosmological history when the universe was only a few hundred million years old.

We have all been asked the big questions at times: “How big is the universe?” or “How and when were galleries created?” Astronauts pay attention to these questions, and use unique tools that push the boundaries of technology to try to answer them. Professor Nobunari Kashikawa from the Department of Astronomy at the University of Tokyo is guided by his curiosity about galaxies. In particular, he asked for the farthest we can look to find out how and when it came to be.

“From previous studies, the galaxy GN-z11 appears to be the most distant galaxy from us, at 13.4 billion light-years, or 134 nonillion kilometers (that’s 134 followed by 30 zeros),” Kashikawa said. “But measuring and determining such a distance is no easy task. ”

Kashikawa and his team measured what is known as the GN-z11 regression; this refers to the way light radiates out, becomes redder, the farther it travels. Some chemical signatures, called transmission lines, show specific patterns in the light from distant objects. By measuring the distance of these signatures, astronomers can determine how far the light must have traveled, thus providing the distance from the galaxy. target.

“We looked at ultraviolet light in particular, as that was the area of ​​the electromagnetic spectrum in which we expected to find the reformed chemical names,” Kashikawa said. “The Hubble Space Telescope has found the signature many times in the GN-z11 spectrum. However, even the Hubble cannot solve ultraviolet emission lines to the level we needed. So we turned to a newer ground-based spectrum, a device for measuring transmission lines, called MOSFIRE, that is mounted to the Keck I telescope in Hawaii. ”

The MOSFIRE captured the transmission lines from GN-z11 in detail, which allowed the team to make a much better estimate of the distance than was possible from previous data. When working with distances at these scales, it does not make sense to use our familiar units of kilometers or even multiples of them; instead, astronomers use a value called the refraction number denoted by z. Kashikawa and his team improved the accuracy of the galaxy’s z value by a factor of 100. If later observations can prove this, astronomers can confidently say that GN-z11 is the longest-discovered galaxy. ever in the universe.

Reference: Linhua, Jiang, et al., Evidence for GN-z11 as a light galaxy at redshift 10.957, Astronomy of Nature (2020). DOI: 10.1038 / s41550-020-01275-y

Press release provided by Tokyo University